Just like MySQL you need to group by in order to use the wm_concat or listagg.
So for an example with just the intermediate table:
Code:
SELECT p.projectid, WM_CONCAT(d.devname)
FROM ProjectDeveloper pd
INNER JOIN Developer d ON d.devid = pd.devid
INNER JOIN Project p ON p.projectid = pd.projectid
WHERE p.projectid = {APROJECTID}
GROUP BY p.projectid
I think something like that would work.
I really should go through my books again anyway; I've forgotten how interesting oracle is.